Multi-directional body motion stack chair

ABSTRACT

The present invention comprises a chair that allows small, subtle multi-directional motion by the user while maintaining the functionality and space requirements of a stack chair. The chair of the present invention comprises motion that is facilitated by flexible supports mounted to the frame of the chair which suspend and support the chair&#39;s seat. A range of motion in the seat is thereby provided which is limited by integrated stopping mechanism built into the chair&#39;s frame. Allowing the user to change seating attitude with concomitant motion of the chair seat improves user comfort and prevents or delays user fatigue during long seating sessions while maximizing efficiency of work accomplished during a seating session.

BACKGROUND OF THE INVENTION

1. Related Application

None

2. Field of the Invention

The invention relates generally to a stackable chair that also facilitates subtle multi-directional body positional and/or attitude adjustment by the user. More specifically, the invention provides in various embodiments a chair seat that is balanced and suspended upon shock absorbers that allow the chair seat to move with the user.

3. Description of the Related Art

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a chair that allows small, subtle multi-directional motion by the user while maintaining the functionality and space requirements of a stack chair. The chair of the present invention comprises motion that is facilitated by flexible supports, i.e., shock absorbers, mounted to the frame of the chair which suspend and support the chair's seat. A range of motion in the seat is thereby provided which is limited by an integrated stopping mechanism built into the chair's frame. Allowing the user to change seating attitude with concomitant motion of the chair seat improves user comfort and prevents or delays user fatigue during long seating sessions while maximizing efficiency of work accomplished during a seating session.

The figures and the detailed description which follow more particularly exemplify these and other embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of one embodiment of the chair of the present invention;

FIG. 2 illustrates a front view of one embodiment of the chair of the present invention;

FIG. 3 illustrates a rear view of one embodiment of the chair of the present invention;

FIG. 4 illustrates a side view of one embodiment of the chair of the present invention;

FIG. 5 illustrates a bottom view of one embodiment of the chair of the present invention;

FIG. 6 illustrates an exploded view of one embodiment of the chair of the present invention;

FIG. 7 illustrates a partial cutaway view of one embodiment of a shock absorber of the present invention;

FIG. 8 illustrates a partial cutaway view of one embodiment of the present invention;

FIG. 9 illustrates a partial cutaway view of one embodiment of a shock absorber of the present invention;

FIGS. 10A and 10B illustrate a partial exploded view of one embodiment of the chair of the present invention; and

FIG. 11 illustrates a partial cutaway view of one embodiment of the present invention.

The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, which are as follows.

DETAILED DESCRIPTION OF THE INVENTION, INCLUDING THE BEST MODE

While the invention is amenable to various modifications and alternative forms, specifics thereof are shown by way of example in the drawings and described in detail herein. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

FIGS. 1-5 provide perspective, front, rear, side and bottom views, respectively, of one embodiment of the chair 100 of the present invention. Chair seat 210 is shown in operative connection and communication with chair legs 310 and further comprising an upper portion 212 in operative connection and communication with a base section 214. Legs 310 further comprise swivel glides 320 operatively disposed and connected at a distal end of each leg 310. The swivel glides 320 are pivotable to allow the chair 100 to accommodate surfaces that are not substantially level as is well known in the art.

FIGS. 6 and 7 provide exploded views of the elements of one embodiment of the chair 100 of the present invention. Thus, an upper section 200 is in operative communication with a lower section 300 of chair 100.

Upper section 200 comprises chair seat 210 discussed supra. Seat 210 may be formed of a variety of materials, including molded plastic, wood and equivalents thereof as is well known to the skilled artisan. Furthermore, the seat 210 is illustrated as a unitary structure comprising the upper portion 212 and seat base 214. However, as the skilled artisan will readily recognize, the seat base 214 may be separated from the upper section 212. Each such equivalent material and seat 210 configuration is within the scope of the present invention.

With reference to the Figures, the seat base 214 of seat 200 comprises an upper side U and a lower side L and will have a geometric center denoted by “C”. Upper section 200 further comprises upper seat plate 220 which is in secured and fixed connection with the lower side L of seat base 214. The secured fixed connection may comprise mechanical securements using, e.g., fasteners 230 of a type well known to the skilled artisan, e.g., rivets or machine screws or the like through pre-drilled holes 232 in upper seat plate 220 and which also engage predrilled holes (not shown) in the lower side L of seat base 214 which align with upper seat plate holes 232 as the skilled artisan will readily understand.

Lower section 300 of chair 100 comprises frame 302 comprising chair legs 310 and a lower base plate 330. Chair legs 310 are in fixed attachment with the lower base plate 330 by, e.g., weldment or other fixed connection solutions well known to the skilled artisan. The lower base plate 330 is thus arranged between the legs 310 which are shown as comprising a front pair F and a rear pair R. With this arrangement, the front and rear pairs F,R of legs are functionally able to stand as illustrated in the Figures. As discussed above, each leg 310 comprises a distal end where a swivel glide 320 is disposed via known mechanical attachment for aid in adapting to flooring that is less than level.

Lower section 300 of chair further comprises a rocker stop bracket 340 in operative connection and communication with lower base plate 330. Side flanges 342 on rocker stop bracket 340 engage the bottom side B of lower base plate 330 while a vertical central section 344 of bracket 340, located between and adjacent the side flanges 342, extends through a complementarily shaped cutout 302 in lower base plate 330. Stop bracket 340 functions to limit the range of motion the upper section 200 of chair can undergo. A preferred profile for the bracket 340 and, as a result for the vertical central section 344, is that of a rectangle. Consequently, the preferred shape for the complementarily shaped cutout 302 is also that of a rectangle. However, a wide variety of geometrical configurations and shapes for bracket 340 and cutout 302 are readily ascertainable by the skilled artisan, including, e.g., and without limitation, square, pentagonal, hexagonal, etc. Each of these equivalent configurations and shapes are within the scope of the present invention.

Further, lower section 300 comprises a bottom cover 350 in operative communication with lower base plate 330 and legs 310 as well as a plurality of stack bumpers 360 in operative communication with the bottom cover 350. As illustrated stack bumpers 360 comprise a predrilled threaded hole therethrough that is engaged by a screw 362 which also threadingly engages predrilled holes 364 in bottom cover 350. A preferred number of stack bumpers 360 is, as illustrated, four, however a number of additional configurations and numbers of stack bumpers 360 are readily ascertainable to the skilled artisan, each of these configurations and numbers of stack bumpers 360 are within the scope of the present invention. Stack bumpers 360 allow several chairs 100 to be stacked upon one another without damage as is known in the art; thus the chair 100 of the present invention is stackable.

Interposed between the upper section 200 and the lower section 300 are a plurality of shock absorbing elements, for example, the illustrated threaded rubber bushings 400. The skilled artisan will recognize a variety of equivalent alternative shock absorbing elements, for example and without limitation, air shock absorbers and spring shock absorbers may be considered possible equivalent alternatives and are, as a result, within the scope of the preset invention. In each embodiment of the present invention, the upper section 200 thus balances on, and is suspended by, the shock absorbing elements, e.g., the illustrated rubber bushings 400. Bushings 400 are in operative communication with the top surface T of lower base plate 330 as well as in operative communication with the bottom surface B′ of upper seat plate 220. A preferred number and configuration of the plurality of shock absorbing elements, e.g., the bushings 400 is, as illustrated, four and in generally a square or rectangular pattern. However, a number of equivalent numbers and configurations of shock absorbing elements, e.g., the bushings 400 will readily present themselves to the skilled artisan; each such equivalent is within the scope of the present invention.

Bushings 400 may comprise a body 402 with a diameter D and a height H and an upward facing nipple 404 rising generally vertically above body 402 and having a diameter D′ smaller than the diameter of body's diameter, creating a shoulder 406 adjacent the nipple 404. Thus, in certain embodiments, the body 402 rests upon the top surface T of lower plate 330 while nipple 404 may comprise a threaded hole therein which may comprise in certain embodiments a threaded stud, and further engage a predrilled hole 410 through the upper seat plate 220 where a screw 408, which may further comprise a securing nut, may secure the upper seat plate 220 to the threated hole in nipple 404 as illustrated in FIGS. 6-8. In certain embodiments, bushings 400′ may comprise a body 402′ with a diameter and no nipple as the skilled artisan will recognize and as illustrated in FIG. 9. In this embodiment, a screw, e.g., 408, may secure the upper seat plate 220 via threaded hole in body 402′ while the lower base plate and body 402′ are secured as described above with a screw and aligned holes.

Further, body 402 may comprise a threaded hole therein which may align with a predrilled hole in lower base plate 330. Thus, body 402 may be secured to lower base plate 330 by engaging the predrilled hole 412 in lower base plate 330 and threadingly engaging the threaded hole in body 402 with a screw 414 as illustrated in FIG. 6. Thus, upper section 200 of chair 100 is effectively suspended upon the rubber bushings 400, primarily by the shoulders 406.

The body 402 of bushings 400 are, in turn secured upon lower section 300 of chair, creating a functional gap between the upper section 200 and lower section 300 of chair. Specifically, a gap is created as best illustrated in FIGS. 8 and 9 between the upper seat plate 220 of the upper section 200 of chair 100 and lower base plate 330 of the lower section 300 of chair 100. The height of the gap will, in an unloaded situation, i.e., without a user seated on chair 100, correspond to the height H of the body 402 of bushings 400. Finally, in certain embodiments such as that illustrated in FIG. 6, bottom cover 350 may further comprise upwardly facing side flanges 352 in order to provide pinch protection wherein the flanges 352 cover the gap created between upper seat plate 220 and lower base plate 330 by the interposing presence of rubber bushings 400.

In certain alternative embodiments, as illustrated in FIGS. 10A and 10B, a shroud 500 may be placed between the upper seat plate 220 and lower base plate 330 in order to provide pinching protection. Shroud 500 may comprise side flanges 502 to cover the gap created between upper seat plate 220 and lower base plate 330 by the interposing presence of rubber bushings 400. In this embodiment, bottom cover 350 does not comprise side flanges 352 as in the embodiment of FIG. 6 because the shroud 500 comprises protective side flanges 502, rendering bottom cover flanges 352 of the embodiment of FIG. 6 unnecessary.

The chair 100 of the present invention thus assembled, a user may sit on chair seat 210 and may sit substantially balanced in the center of the chair seat 210, suspended on the shock absorbing elements, e.g., rubber bushings 400. In this case, the mass of the user is substantially equally displaced through the rubber bushings 400 upon which the upper section 200 of the chair 100 rests. This is illustrated by the “x” in FIG. 8, corresponding to the general center of mass of the user seated on chair seat 210 and transmitted down to upper seat plate 220. In other words, the rubber bushings 400 will, in this instance, be substantially equally loaded and the chair seat 210 retains its initial non-deformed attitude and position but is slightly lower. This is achieved by a slight compression of the bushing body 402, each body 402 compressing substantially the same amount. Thus, the chair seat 210 comprises an initial attitude and position wherein the user's weight is substantially balanced in the center of chair seat 210. In this position, the rubber bushings 400 may be compressed, but are substantially equally compressed. Stated differently, the height H of shock absorbing elements, e.g., bushings 400, is less than H, e.g., H′ as in FIG. 7, when a user is seated on chair 100 than when no user is seated because the bushings compress. In this case, the height of each of the compressed bushings 400 is approximately the same, i.e., H′ as illustrated by the dashed line and bi-directional arrows.

If, however, during the course of a seating session, the user wishes to shift his or her position or attitude, the chair seat 210 will respond to this position shift with a concomitant change of position. This change of position of chair seat 210 is in response to the change of weight distribution when the user changes his or her position. An exemplary situation is illustrated in FIG. 11, wherein two bushings 400 are illustrated with a body 402 and nipple 406 in secured and operational connection and communication with upper plate 220 and lower base plate 330. Base plate 330 does not move in response to a shift in user's weight. In this case, as opposed to the balanced situation shown in FIG. 8, the user's center of mass, denoted by “x” is no longer centered and balanced on chair seat but has shifted to one side. In this situation, the weight of the user is not equally displaced through the rubber bushings 400, i.e., the rubber bushings 400 will not be loaded equally and at least one of the rubber bushings 400 will comprise a compressed deformation away from the balanced situation described above wherein the user's weight is substantially centered in the chair seat 210. This is illustrated by the bushing 400 that is furthest from the center of mass “x” comprising an essentially uncompressed height H, while the bushing 400 that is closer to the shifted center of mass “x” is compressed, indicated as height H′, which is shorter than H. Thus, since the rubber bushings 400 flex and compress, the chair seat 210 will change its position in response. Thus, the chair seat 210 comprises a second loaded attitude and position wherein the chair seat 210 moves in response to the user's shifted weight, i.e., shifted away from being substantially equally displaced to substantially unequally displaced. Stated differently, the upper section 200 of the chair 100, which is suspended and balanced on the rubber bushings 400, is allowed by the present invention to change its position and attitude in the direction of the user's weight shift.

As the seating session progresses, the user may shift his or her weight multiple times. In response, the weight shifts of the user are transferred through the chair seat 210 and the upper plate 220 to the rubber bushings 400 suspending the upper section 200 of the chair 100. The rubber bushings 400 deform accordingly in response to the transferred weight shift and displacement, allowing the upper section 200 of the chair 100, to shift in the direction of the weight shift of the user.

Generally, at least one shock absorbing element, e.g., rubber bushing 400 will compress when the user's center of mass shifts away from the center of the chair seat 210. Thus, each of the plurality of shock absorbing elements, e.g., rubber bushing 400, are capable of independently compressing in response to weight changes or shifts of weight or center of mass of the user on the chair seat 210. This independent compression for each shock absorbing element allows the chair seat 210 to move in response to provide the user with a more comfortable seating experience.

Thus, the present invention may accommodate what the skilled artisan will now recognize as an infinite number of positional directional and attitudinal changes of weight balance by the user, the magnitude of which is limited in the present invention by the presence of rocker stop bracket 340 which stops the chair seat 210 motion when engaged.

The present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification. 

What is claimed is:
 1. A stackable chair comprising: an upper section comprising a chair seat having a center; a lower section in operative communication and connection with the upper section; and a plurality of shock absorbing elements operationally interposed between the upper section and the lower section, each of the plurality of shock absorbing elements in operative communication and connection with the upper section and with the lower section and further comprising an uncompressed height and wherein each one of the plurality of shock absorbing elements is capable of independent compression in response to pressure changes on the chair seat whereupon a compressed height is achieved by at least one of the plurality of shock absorbing elements that is lower than the uncompressed height.
 2. The stackable chair of claim 1, wherein the upper section comprises: a chair seat having seat base having an upper side and a lower side; and an upper seat plate in fixed secured connection with the lower side of seat base;
 3. The stackable chair of claim 1, wherein the chair seat further comprises an upper portion, wherein the upper portion and seat base are formed as a unitary structure.
 4. The stackable chair of claim 1, wherein the lower section comprises: a frame comprising a front pair of chair legs, a rear pair of chair legs and a lower base plate having a bottom side and cutout therethrough, the cutout having a profile and shape, the base plate in fixed attachment with the front and rear pairs of chair legs; a rocker stop bracket in operative connection and communication with the cutout of lower base plate, rocker stop bracket further comprising side flanges that engage the bottom side of lower base plate, a vertical central section located between and adjacent the side flanges, the vertical central section comprising a profile that is complementary to the profile of base plate cutout, wherein the vertical central section engages and extends through the complementarily shaped cutout in lower base plate when side flanges engage the bottom side of lower base plate.
 5. The stackable chair of claim 4, wherein the lower section further comprises: a bottom cover in operative communication with lower base plate; and a plurality of stack bumpers in operative communication with the bottom cover.
 6. The stackable chair of claim 4, wherein the bottom cover further comprises upwardly facing side flanges.
 7. The stackable chair of claim 4, further comprising a protective shroud 500 disposed between the upper seat plate and lower base plate wherein the protective shroud comprises side flanges.
 8. The stackable chair of claim 4, further comprising each leg of the front and rear pairs of legs comprising a distal end where a swivel glide is attached.
 9. The stackable chair of claim 4, wherein the plurality of shock absorbing elements comprise a plurality of compressible rubber bushings having a body with a diameter.
 10. The stackable chair of claim 9, wherein each of the plurality of compressible rubber bushings further comprise an upwardly facing nipple rising generally vertically above the body of the compressible rubber bushing, the nipple having a diameter that is less than the diameter of the rubber bushing's body, and a shoulder adjacent the nipple.
 11. The stackable chair of claim 9, wherein each of the plurality of compressible rubber bushings comprise a threaded hole in the nipple and a threaded hole in the body, wherein the nipple aligns with and engages a predrilled hole through the upper seat plate, wherein a fastener secures the upper seat plate to the threaded hole in the nipple and wherein the shoulder of the compressible rubber bushing engages the bottom surface of upper seat plate.
 12. The stackable chair of claim 11, wherein the body of each of the plurality of compressible rubber bushings comprises a threaded hole therein, each threaded hole in alignment with a predrilled hole in the lower base plate, wherein a fastener secures the body of the compressible rubber bushing to the lower base plate.
 13. The stackable chair of claim 11, further comprising a gap established between the upper section and the lower section of the chair, wherein the gap corresponds to the height of the body of the bushings.
 14. The stackable chair of claim 11, wherein the preferred complementary profiles for the base plate cutout and the rocker stop bracket is rectangular.
 15. The stackable chair of claim 1, wherein the plurality of stock absorbing elements comprise air shock absorbers.
 16. The stackable chair of claim 1, wherein the plurality of shock absorbing elements comprise springs.
 17. A stackable chair comprising: a chair seat having seat base having an upper side and a lower side; an upper seat plate in fixed secured connection with the lower side of seat base; a frame comprising a front pair of chair legs, a rear pair of chair legs and a lower base plate having a bottom side and cutout therethrough, the cutout having a profile and shape, the base plate in fixed attachment with the front and rear pairs of chair legs; a rocker stop bracket in operative connection and communication with the cutout of lower base plate, rocker stop bracket further comprising side flanges that engage the bottom side of lower base plate, a vertical central section located between and adjacent the side flanges, the vertical central section comprising a profile that is complementary to the profile of base plate cutout, wherein the vertical central section engages and extends through the complementarily shaped cutout in lower base plate when side flanges engage the bottom side of lower base plate; a bottom cover in operative communication with lower base plate; a plurality of stack bumpers in operative communication with the bottom cover; a plurality of independently compressible rubber bushings having a body with a diameter, wherein each of the plurality of compressible rubber bushings further comprise an upwardly facing nipple rising generally vertically above the body of the compressible rubber bushing, the nipple having a diameter that is less than the diameter of the rubber bushing's body, and a shoulder adjacent the nipple, wherein each of the plurality of compressible rubber bushings further comprise a threaded hole in the nipple and a threaded hole in the body, wherein the nipple aligns with and engages a predrilled hole through the upper seat plate, wherein a fastener secures the upper seat plate to the threaded hole in the nipple and wherein the shoulder of the compressible rubber bushing engages the bottom surface of upper seat plate, wherein the body of each of the plurality of compressible rubber bushings comprises a threaded hole therein, each threaded hole in alignment with a predrilled hole in the lower base plate, wherein a fastener secures the body of the compressible rubber bushing to the lower base plate; and a gap established between the upper seat plate and lower base plate, wherein the gap corresponds to the height of the body of the bushings
 18. A method for providing a chair with a base that moves in response to a user's shifting weight, comprising: providing a chair with an upper section comprising a chair seat having a center and an upper seat plate fixed to the chair seat; providing a chair with a lower section comprising a frame having legs and a lower base plate, wherein the upper section and the lower section are in operative communication and connection; providing a plurality of shock absorbing elements interposed between the upper section and the lower section, whereupon the upper section is suspended.
 19. The method of claim 18, wherein each of the plurality of shock absorbing elements compress substantially equally when the user's center of mass is substantially centered on the chair seat.
 20. The method of claim 19, wherein at least one of the plurality of shock absorbing elements compressing more than the other of the plurality of shock absorbing elements in response to a shifting of the user's center of mass away from the substantial center of the chair seat. 